输入四个字符后如何编写UItextfield长度和更改键盘数字格式的条件

Posted 2023-03-11

【中文标题】输入四个字符后如何编写UItextfield长度和更改键盘数字格式的条件

【英文标题】：how to write the condition for UItextfield length and changing keyboard number format after entering four char

【发布时间】：2017-03-08 06:25:43

【问题描述】：

在 Uitextfield 长度 6 中，前四个字符必须是字符串，当我输入前四个字符时，两个必须是数字，我尝试输入第 5 个字符键盘更改为数字格式，那么我如何在目标 c 中编写上述条件。

【参考方案1】：

- (BOOL)textField:(UITextField *)textField
shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString *)string


   // NSLog(@"%d",range);
 NSString * r = [NSString stringWithFormat:@"%d", range];
 NSLog(@"%@",r);
 if ([r  isEqual: @"4"])
 
    [_txtView setKeyboardType:UIKeyboardTypeNumberPad];
    [self.view endEditing:YES];
    [_txtView becomeFirstResponder];

 


 return YES;

【参考方案2】：

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool

您可以使用此委托函数并根据您的要求添加所有必要条件。下面我展示了一些示例通用代码。您也可以键盘根据文本长度输入

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool


    //length condition and also trim the string before yu check for space and dot(.)
    if(textField.text?.characters.count == 6)
        return false
    

    //alphabetic condition
    if((textField.text?.characters.count <= 4))

        if(string == "number")
            return false
        
    else if((textField.text?.characters.count > 4  ))
        if(string == "alphabetic"  )
            return false
        

    

    return true

【参考方案3】：

可以使用其属性keyboardType 以编程方式更改键盘类型。由于您必须检查每个输入，您需要实现shouldChangeCharactersInRange 的UITextFieldDelegate 的委托方法。

以下是一个示例，您可以对其进行优化以减少重新加载的次数。

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

    if (textfield == <Your texfield>)  // this condition is required in case of multiple textfields in the same view else you can skip
        NSString *finalString = [textField.text stringByReplacingCharactersInRange:range withString:string];
        if (finalString.length <= 6) 
            if (finalString.length > 3) 
                textField.keyboardType = UIKeyboardTypePhonePad;
             else 
                textField.keyboardType = UIKeyboardTypeDefault;
            
            [textField reloadInputViews];
         else 
            return NO;
        
    

【参考方案4】：

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 
if (string.length == 0) 
    if (textField.text.length == 4) 
        textField.keyboardType = UIKeyboardTypeDefault;
        textField.resignFirstResponder;
        textField.becomeFirstResponder;
    
 else 
    if (textField.text.length == 3) 
        textField.keyboardType = UIKeyboardTypeNumberPad;
        textField.resignFirstResponder;
        textField.becomeFirstResponder;
        return NO;
     if (textField.text.length < 4) 
        NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:@"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"] invertedSet];
        NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
        return [string isEqualToString:filtered];
     else if (textField.text.length == 6) 
        return YES;
    


return true;